1. Field of the Invention
The present invention relates to an obstacle determination system and method, and in particular to an obstacle determination system and method that can be utilized in achieving safe driving of a vehicle.
2. The Prior Arts
With the decreasing cost of camera, presently, camera-related photographic apparatuses are widely utilized in assisting safe vehicle driving. However, most of them are only capable of providing images around a vehicle passively in assisting driver of a vehicle in avoiding occurrences of accidents. Since it is rather difficult for a driver to monitor a plurality of display screens simultaneously, and the scope of visual dead angle (blind spot) is still rather large for applying conventional planar images in assisting driving and parking of a vehicle. Therefore, presently, a virtual surrounding bird's-eye-view imaging system is developed and produced, that can overlook from the top of the vehicle through a plurality of cameras installed around the vehicle, so that a plurality of images obtained are combined into a top view image having a transformed visual angle, that is more suitable for and compatible with the visual habit of human eyes, and that can be utilized to overcome the shortcomings of visual dead angles.
However, usually, in transforming a planar image into a surrounding bird's-eye-view image for an ordinary surrounding bird's-eye-view imaging system, since a plurality of images have to be combined at the same time, therefore, in case that an object of a certain height appears in the overlapped region, then this object can not appear on the surrounding images due to the dead angles of image stitching. Therefore, this kind of existing surrounding imaging technology still has much room for improvements.
In order to overcome the shortcomings of this kind of surrounding imaging technology, in the conventional technology, radars or ultrasonic devices are utilized to detect the existence of obstacles, then the image thus obtained are stitched with the images taken by cameras, and when an obstacle at a stitched position of the images is detected, an audio or visual alarm will be issued to remind the driver that the obstacle exists in that position. By way of example, in a Japanese patent publication No. JP 2007041791 (A) is disclosed a bird's-eye-view image displaying system and method. Wherein, a plurality of cameras installed on a vehicle are used to obtain images around a vehicle, and then the images thus obtained are stitched into a surrounding bird's-eye-view image, and from this image, it can be known if an obstacle exists in front, rear, left side, or right side of a vehicle. In order to overcome the problem that an obstacle of a certain height is rather difficult to appear or indicate at a stitched position of surrounding images, four ultrasonic devices are utilized in that patent case to detect the dead angle regions. Though, this kind of approach is able to overcome this problem, yet it could increase the overall cost of the system for utilizing ultra sonic devices.
In addition, in the prior art, in a two-dimensional surrounding bird's-eye-view imaging system, the virtual viewpoint is set at a fixed point above the vehicle, so the scopes of the bird's-eye-view image in response to the virtual viewpoint can't be changed with driving condition. However, in moving forward, backward or turning around a corner of a vehicle, the scopes of fields of view of an imaging region in the vehicle moving direction are different as dictated by the actual requirement of a vehicle driver. Yet, in the prior art, only the bird's-eye-view images of a fixed virtual visual angle are provided, that can hardly fulfill the requirement of a vehicle driver.